Effects of two angiotensin converting enzyme inhibitors on the mechanical function and energy metabolism of isolated rat hearts. A nuclear magnetic resonance study with an active form of benazeprilat and captopril.
The effects of angiotensin converting enzyme inhibitors (ACEIs), CGS 14831 (CAS 86541-78-8) and captopril, on the mechanical function and energy metabolism were studied in isolated rat hearts using global ischemia-reperfusion model. The myocardial tissue levels of ATP, creatine phosphate (CP) and pH were determined with 31P-nuclear magnetic resonance (31P-NMR). Global ischemia was induced by cross-clamping of the inflow line for 40 min. While thiol containing ACEI, captopril, significantly inhibited the ATP depletion and pH fall produced by ischemia, non-thiol compound, CGS 14831, did not have any influence on the ATP degradation and pH fall during ischemia. Both CGS 14831 (20 micrograms/ml) and captopril (80 micrograms/ml) have little influence on the mechanical function during the ischemia-reperfusion period. L-Cysteine (44.6 micrograms/ml) inhibited the pH fall significantly during the ischemia without exerting influence on the ATP degradation. These data suggest that local renin-angiotensin-aldosterone system does not play an important role in maintenance of the myocardial mechanical function during ischemia-reperfusion. The thiol residue of captopril is not responsible for the inhibitory effect of this compound on ischemia-induced ATP degradation. Some specific effect of captopril may play a role in the protective effect.
Tanaka
M
M
Department of Pharmacology, Niigata University School of Medicine, Japan.
Ishibashi
T
T
Imai
S
S
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology*; D000818:Animals; D001552:Benzazepines / Q000494:pharmacology; D002216:Captopril / Q000494:pharmacology; D004734:Energy Metabolism / Q000187:drug effects; D006321:Heart / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects*; D015425:Myocardial Reperfusion; D051381:Rats; D011919:Rats, Inbred Strains
D000806:Angiotensin-Converting Enzyme Inhibitors; D001552:Benzazepines; D002216:Captopril; C052133:benazeprilat